Re: [PATCH net] ipv6: Add lwtunnel encap size of all siblings in nexthop calculation

[luwei (O)]

ok, I will send v2 version

在 2023/2/14 11:45 PM, David Ahern 写道:
> On 2/14/23 2:29 AM, Lu Wei wrote:
> > In function rt6_nlmsg_size(), the length of nexthop is calculated
> > by multipling the nexthop length of fib6_info and the number of
> > siblings. However if the fib6_info has no lwtunnel but the siblings
> > have lwtunnels, the nexthop length is less than it should be, and
> > it will trigger a warning in inet6_rt_notify() as follows:
> >
> > WARNING: CPU: 0 PID: 6082 at net/ipv6/route.c:6180 inet6_rt_notify+0x120/0x130
> > ......
> > Call Trace:
> >   <TASK>
> >   fib6_add_rt2node+0x685/0xa30
> >   fib6_add+0x96/0x1b0
> >   ip6_route_add+0x50/0xd0
> >   inet6_rtm_newroute+0x97/0xa0
> >   rtnetlink_rcv_msg+0x156/0x3d0
> >   netlink_rcv_skb+0x5a/0x110
> >   netlink_unicast+0x246/0x350
> >   netlink_sendmsg+0x250/0x4c0
> >   sock_sendmsg+0x66/0x70
> >   ___sys_sendmsg+0x7c/0xd0
> >   __sys_sendmsg+0x5d/0xb0
> >   do_syscall_64+0x3f/0x90
> >   entry_SYSCALL_64_after_hwframe+0x72/0xdc
> >
> > This bug can be reproduced by script:
> >
> > ip -6 addr add 2002::2/64 dev ens2
> > ip -6 route add 100::/64 via 2002::1 dev ens2 metric 100
> >
> > for i in 10 20 30 40 50 60 70;
> > do
> > 	ip link add link ens2 name ipv_$i type ipvlan
> > 	ip -6 addr add 2002::$i/64 dev ipv_$i
> > 	ifconfig ipv_$i up
> > done
> >
> > for i in 10 20 30 40 50 60;
> > do
> > 	ip -6 route append 100::/64 encap ip6 dst 2002::$i via 2002::1
> > dev ipv_$i metric 100
> > done
> >
> > ip -6 route append 100::/64 via 2002::1 dev ipv_70 metric 100
> would be good to add that test to
>     tools/testing/selftests/net/fib_tests.sh
>
> along with a similar one for IPv4.
>
> > This patch fixes it by adding nexthop_len of every siblings using
> > rt6_nh_nlmsg_size().
> >
> > Fixes: beb1afac518d ("net: ipv6: Add support to dump multipath routes via RTA_MULTIPATH attribute")
> > Signed-off-by: Lu Wei <luwei32@xxxxxxxxxx>
> > ---
> >   net/ipv6/route.c | 11 ++++++-----
> >   1 file changed, 6 insertions(+), 5 deletions(-)
> Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
>
>
> .

--
Best Regards,
Lu Wei